Brief introduction of various processes of film-coated butyl rubber plugs

Although the internal cleanliness, chemical stability, airtightness, and biological performance of butyl rubber stoppers are all good, due to the complexity of the formula and the concentration gradient of the raw materials added, they are encapsulated by drugs that have strong activity against some molecules. Drug absorption, adsorption, leaching, and infiltration produced compatibility issues between the rubber stopper and the drug. Some of the more prominent were cephalosporins, some large infusions, and more traditional Chinese medicine injection preparations. Therefore, through the use of an inert soft coating covering the surface of the rubber plug to isolate the direct contact between the drug and the rubber stopper, the compatibility with the drug can be significantly improved.

Advantages of film-covered butyl rubber plugs: Through the formation of a film on the surface of rubber plugs, it can effectively reduce the absorption, adsorption, leaching and infiltration between rubber plugs and drugs, improve the long-term stability of drugs, and improve the mechanical lubrication of rubber plugs. Sex; greatly reduces the amount of insoluble particles in the liquid due to silicone oil.

Membrane material requirements

Including: extremely low gas permeability; extremely strong resistance to water vapour permeability; very high chemical resistance; very high heat aging resistance; high internal cleanliness; good resistance to ozone and weathering Sex; Steady radiation disinfection; It should be non-toxic, odorless, non-polluting; It should have good elasticity.

Commonly used film materials

According to the characteristics of the film material, the most commonly used film materials are the following: polydimethylsiloxane film, parylene film, polyETFE film, polyester film and so on.

Process Introduction

1. Foil technology

The membranes used in this technology are mostly poly-ETFE membranes, Teflon membranes, polyethylene membranes, and polypropylene membranes. The membrane has strong adhesion and is not easy to fall off. However, the membrane material has poor elasticity and the membrane plug rubber has a large hardness and is easy to appear. Sealing problem.

This process can be further divided into three types:
A. A full-coverage rubber stopper is prepared by a single molding process as follows:
1 membrane surface activation treatment (chemical or physical method, generally single-sided treatment);
2 The film is covered with a film (the surface on which the film is activated is affixed to the uncured compounded film);
3 vacuum molding vulcanization molding;
4 molding rubber plug (can be the neck and sealing surface coating, but also for the full coating of the neck, crown);
5 die cut.
B. The secondary molding method to prepare the covered rubber plug, the process is as follows:
1 membrane surface activation treatment (chemical, physical);
2 mixing film on the film;
3 vacuum molding vulcanization molding;
4 neck molding;
5 neck punching;
6 neck and crown vulcanization bonding molding;
7 neck coating plastic plug;
8 die cut.
C. Adhesive-molded film-covered rubber plugs. This process involves first producing rubber plugs, applying a layer of adhesive to the surface of the rubber plugs, compressing the film into rubber plugs, and applying pressure to the rubber plugs. Tightening can be. The key to this technology lies in the choice of adhesive and how to apply it uniformly. Otherwise, peeling or film peeling will occur, which will affect the use.

2. Dipping, spraying and brushing techniques

Dip coating, spray coating and brush coating have similarities. This process is usually activated by the surface of the precursor rubber plug, and then it is chemically grafted with the grafted material. This forms a layer of inertness on the plug surface. membrane.

3. Vacuum coating process

The coating material used for this process on butyl rubber plugs is usually poly-parylene. Parylene is a unique polymer with thermal post-plasticity. The Parylene coating process is at room temperature and vacuum. It can be penetrated and covered on the objects to be processed. The film is uniform and transparent. It is a real pinhole-free coating film that can prevent moisture, acid, alkali, bacteria, weather and heat. (Using temperature up to 275 degrees), anti-cold (minus 200 degrees).
Parylene deposition is the first step. The solid feedstock p-xylene is evaporated at a temperature of about 150°C. The second step is the cleavage of two side chain carbon-carbon chains at a temperature of 680°C to form a stable reactive monomer. The last activity is. The monomer is polymerized and deposited in a deposition chamber at room temperature and instantaneously adsorbed on the substrate to be polymerized into a parylene film. The remaining gas is trapped by the cold trap to prevent sediment from entering the vacuum pump.

summary

The coating process of butyl rubber plugs is constantly being explored and optimized by many manufacturers. Everyone is looking for a simple and fast process that can be produced in batches to meet the needs of pharmaceutical companies.

Source: Packaging Materials and Containers